﻿<html>
 <body>
 <p> 点击下面的按钮，只要i小于5就一直循环代码块。</p>
 <button onclick="myFunction()">点击这里</button>
   <p id="demo"> </p>
   <script>
     function myFunction(){
	  var x = "",i=0;
	while(i<5){
	 x =x +"The number is " + i + "<br>";
	 i++;
	}
	document.getElementById("demo").innerHTML=x;
}
 </script>
    
		
<script>
	 cars  = ["BMW","Volvo","Saab","Ford"];
	 var i=0;
	 for(; cars[i];){
	  document.write(cars[i]+"<br>");
	  i++;
	 }
</script>
		
 </body>
 </html>